A comparator 4 generates a signal for resetting a latch circuit 5 based on the current signal IL representing an electric current ?oWing through the inductor L, the control
signal 1cm, generated by the feedback ampli?er 1, and the ramp signal generated by the ramp signal generating circuit 3. Speci?cally, the comparator 4 generates the reset signal if the total of the current signal IL and the ramp signal is larger than the control signal 1cm].